The giant-impact hypothesis, sometimes called the Big Splash, or the Theia Impact suggests that the Moon formed out of the debris left over from a collision between Earth and an astronomical body the size of Mars, approximately 4.5 billion years ago, in the Hadean eon; about 20 to 100 million years after the solar system coalesced. The colliding body is sometimes called Theia, from the name of the mythical Greek Titan who was the mother of Selene, the goddess of the Moon. Analysis of lunar rocks, published in a 2016 report, suggests that the impact may have been a direct hit, causing a thorough mixing of both parent bodies.

How about there was an impact ~4.5bya between early Earth and early Moon (much smaller than Mars), and that's why there're dark and light patches on the Moon, and continents and sea floors on Earth? Where originally after such an impact, material from both bodies became mixed on Earth's surface. Early Moon hit early Earth at an angle rather than head on, and vast ammounts of surface material from early Moon was "sheared" off and made part of the surface of Earth, which then formed Earth's continents and Moon's dark patches. It would serve to explain why the far side of the Moon has no dark patches at all, and why Earth's continents were one big land mass (Pangaea) untill a few hundred million years ago. It would explain plate tectonics, because the material of those two early bodies were "incompatible" of sorts, so one "floats" on top of another (though extremely slowly through continental drift). So when you see the dark patches on the Moon today, that is the side of the ancient impact, while the side of the Pacific represents the side of Earth, that wasn't impacted.

Isn't it possible to confirm or reject this? Maybe via geochemical similarities between Apollo samples from light lunar patches and the general composition of Earth's continents, that isn't comparable to the composition of dark lunar patches and Earth's sea floors?

November 8th, 2017, 08:46 PM

Paleoichneum

No the two bodies are not the same geochemically, they are "similar" but NOT the same, as that is explained in with the existing hypothesis. There would be areas of vastly different geochemical makeup if your supposed glancing blow happened. Plus this ignores that that earths continents are not at all Geochemically the same to each other, and are far from geochemically the same within themselves.